We propose to investigate producing medical radioisotopes with photons generated by an electron beam. Although protons enjoy a hundred-fold cross section advantage over photons, their energy loss to ionization restricts the target volume while the long photon attenuation length allows large volume targets to be used. We show here that these effects compensate and the activities generated can be comparable, an unappreciated fact. Further, many hospitals have shown that electron accelerators are easy to site and run and relatively inexpensive to purchase and operate. We are building a 70 MeV electron Race-Track Microtron that is smaller, more reliable, more efficient, less expensive, and easier to operate than either hospital cyclotrons or electron LINACs. We show here, by simulations using four PET radioisotopes as an example, that yields and specific activities sufficient for most clinical and research needs can be produced. We now must refine and extend these calculations to other medical interesting radioisotopes and also experimentally verify our predictions for a few of these isotopes. If we are funded and if our Phase I results are encouraging, we will propose in Phase II to build a prototype photoproduction medical radioisotope facility. PROPOSED COMMERCIAL APPLICATIONS: Success in the work proposed here will result in a new facility for producing medical radioisotopes that is less expensive to construct and operate and that requires less space than present facilities. These economies should make a wider variety of radionuclei applications available to a larger number of clinicians.